Can you explain every single part of this code to me$?$ thank you! Is there anything different I could do to improve this code?

#include

#define PIN$\_$Motor$\_$AIN$\_17$

#define PIN$\_$Motor$\_$PWMB $6$

#define PIN$\_$Motor$\_$PWMA $5$

#define PIN$\_$Motor$\_$BIN$\_18$

#define PIN$\_$Motor$\_$STBY $3$

#define ECHO$\_$PIN $12$

#define TRIG$\_$PIN $13$

#define FULL$\_$SPEED $150$

#define CAUTION$\_$SPEED $50$

#define CLOSE$\_$ENOUGH$\_$DISTANCE $50$

#define TOO$\_$CLOSE$\_$DISTANCE $10$

#define ENOUGH$\_$SPACE$\_$DISTANCE $110$

#define BACKUP$\_$DISTANCE $20$

Servo servo;

int angle $=90$;

struct Distances $\{$

int left;

int right;

$\}$;

void setup$()\{$

Serial.begin$(9600)$;

pinMode$($PIN$\_$Motor$\_$PWMA, OUTPUT$)$;

pinMode$($PIN$\_$Motor$\_$PWMB$,$ OUTPUT$)$;

pinMode$($PIN$\_$Motor$\_$AIN$\_1,$ OUTPUT$)$;

pinMode$($PIN$\_$Motor$\_$BIN$\_1,$ OUTPUT$)$;

pinMode$($PIN$\_$Motor$\_$STBY$,$ OUTPUT$)$;

pinMode$($TRIG$\_$PIN, OUTPUT$)$;

pinMode$($ECHO$\_$PIN, INPUT$)$;

servo.attach$(10)$;

servo.write$($angle$)$;

$\}$

void loop$()\{$

digitalWrite$($PIN$\_$Motor$\_$STBY$,$ HIGH$)$;

float distance $=$ readPing$()$;

if $($distance $>$ ENOUGH$\_$SPACE$\_$DISTANCE$)\{$

moveForward$($FULL$\_$SPEED$)$;

$\}$ else if $($distance $>$ CLOSE$\_$ENOUGH$\_$DISTANCE && distance $<=$ ENOUGH$\_$SPACE$\_$DISTANCE$)\{$

moveForward$($CAUTION$\_$SPEED$)$;

$\}$ else if $($distance $>$ TOO$\_$CLOSE$\_$DISTANCE && distance $<=$ CLOSE$\_$ENOUGH$\_$DISTANCE$)\{$

Distances distances $=$ Peer$()$;

if $($distances$.$right $>=$ distances.left$)\{$

turnRight$()$;

$\}$ else $\{$

turnLeft$()$;

$\}$

delay$(1500)$;

$\}$ else $\{$

moveBackward$()$;

delay$(1000)$;

Stop$()$;

delay$(1000)$;

$\}$

$\}$

Distances Peer$()\{$

Distances distances;

lookLeft$()$;

delay$(1000)$;

distances.left $=$ readPing$()$;

lookStraight$()$;

delay$(500)$;

lookRight$()$;

delay$(1000)$;

distances.right $=$ readPing$()$;

lookStraight$()$;

delay$(500)$;

return distances;

$\}$

int readPing$()\{$

digitalWrite$($TRIG$\_$PIN, LOW$)$;

delayMicroseconds$(2)$;

digitalWrite$($TRIG$\_$PIN, HIGH$)$;

delayMicroseconds$(10)$;

digitalWrite$($TRIG$\_$PIN, LOW$)$;

unsigned long duration$\_$us $=$ pulseIn$($ECHO$\_$PIN, HIGH$)$;

float distance$\_$cm $=0\mathrm{.}017*$ duration$\_$us;

Serial.print$("$distance: $")$;

Serial.print$($distance$\_$cm$)$;

Serial.println$("$ cm$")$;

return distance$\_$cm;

$\}$

void Stop$()\{$

digitalWrite$($PIN$\_$Motor$\_$AIN$\_1,$ HIGH$)$;

analogWrite$($PIN$\_$Motor$\_$PWMA, $0)$;

digitalWrite$($PIN$\_$Motor$\_$BIN$\_1,$ HIGH$)$;

analogWrite$($PIN$\_$Motor$\_$PWMB$,0)$;

$\}$

void moveForward$($int speed$)\{$

digitalWrite$($PIN$\_$Motor$\_$AIN$\_1,$ HIGH$)$;

analogWrite$($PIN$\_$Motor$\_$PWMA, speed$)$;

digitalWrite$($PIN$\_$Motor$\_$BIN$\_1,$ HIGH$)$;

analogWrite$($PIN$\_$Motor$\_$PWMB$,$ speed$)$;

$\}$

void moveBackward$()\{$

digitalWrite$($PIN$\_$Motor$\_$AIN$\_1,$ LOW$)$;

analogWrite$($PIN$\_$Motor$\_$PWMA, FULL$\_$SPEED$)$;

digitalWrite$($PIN$\_$Motor$\_$BIN$\_1,$ LOW$)$;

analogWrite$($PIN$\_$Motor$\_$PWMB$,$ FULL$\_$SPEED$)$;

$\}$

void lookRight$()\{$

Stop$()$;

servo.write$(150)$;

$\}$

void lookStraight$()\{$

Stop$()$;

servo.write$(90)$;

$\}$

void lookLeft$()\{$

Stop$()$;

servo.write$(40)$;

$\}$

void turnLeft$()\{$

digitalWrite$($PIN$\_$Motor$\_$AIN$\_1,$ HIGH$)$;

analogWrite$($PIN$\_$Motor$\_$PWMA, $0)$;

digitalWrite$($PIN$\_$Motor$\_$BIN$\_1,$ HIGH$)$;

analogWrite$($PIN$\_$Motor$\_$PWMB$,100)$;

$\}$

void turnRight$()\{$

digitalWrite$($PIN$\_$Motor$\_$AIN$\_1,$ HIGH$)$;

analogWrite$($PIN$\_$Motor$\_$PWMA, $100)$;

digitalWrite$($PIN$\_$Motor$\_$BIN$\_1,$ HIGH$)$;

analogWrite$($PIN$\_$Motor$\_$PWMB$,0)$;

$\}$